8 research outputs found
A study of the lunisolar secular resonance
The dynamics of small bodies around the Earth has gained a renewed interest,
since the awareness of the problems that space debris can cause in the nearby
future. A relevant role in space debris is played by lunisolar secular
resonances, which might contribute to an increase of the orbital elements,
typically of the eccentricity. We concentrate our attention on the lunisolar
secular resonance described by the relation ,
where and denote the argument of perigee and the longitude of
the ascending node of the space debris. We introduce three different models
with increasing complexity. We show that the growth in eccentricity, as
observed in space debris located in the MEO region at the inclination about
equal to , can be explained as a natural effect of the secular
resonance , while the chaotic variations of the
orbital parameters are the result of interaction and overlapping of nearby
resonances.Comment: 15 pages, 8 figure
A study of the main resonances outside the geostationary ring
We investigate the dynamics of satellites and space debris in external
resonances, namely in the region outside the geostationary ring. Precisely, we
focus on the 1:2, 1:3, 2:3 resonances, which are located at about 66 931.4 km,
87 705.0 km, 55 250.7 km, respectively. Some of these resonances have been
already exploited in space missions, like XMM-Newton and Integral.
Our study is mainly based on a Hamiltonian approach, which allows us to get
fast and reliable information on the dynamics in the resonant regions.
Significative results are obtained even by considering just the effect of the
geopotential in the Hamiltonian formulation. For objects (typically space
debris) with high area-to-mass ratio the Hamiltonian includes also the effect
of the solar radiation pressure. In addition, we perform a comparison with the
numerical integration in Cartesian variables, including the geopotential, the
gravitational attraction of Sun and Moon, and the solar radiation pressure.
We implement some simple mathematical tools that allows us to get information
on the terms which are dominant in the Fourier series expansion of the
Hamiltonian around a given resonance, on the amplitude of the resonant islands
and on the location of the equilibrium points. We also compute the Fast
Lyapunov Indicators, which provide a cartography of the resonant regions,
yielding the main dynamical features associated to the external resonances. We
apply these techniques to analyze the 1:2, 1:3, 2:3 resonances; we consider
also the case of objects with large area-to-mass ratio and we provide an
application to the case studies given by XMM-Newton and Integral.Comment: 30 pages, 10 figure
Resonances in the Earth's Space Environment
We study the presence of resonances in the region of space around the Earth.
We consider a massless body (e.g, a dust particle or a small space debris)
subject to different forces: the gravitational attraction of the geopotential,
the effects of Sun and Moon. We distinguish different types of resonances:
tesseral resonances are due to a commensurability involving the revolution of
the particle and the rotation of the Earth, semi-secular resonances include the
rates of variation of the mean anomalies of Moon and Sun, while secular
resonances just depend on the rates of variation of the arguments of perigee
and the longitudes of the ascending nodes of the perturbing bodies. We
characterize such resonances, giving precise statements on the regions where
the resonances can be found and provide examples of some specific
commensurability relations.Comment: 38 pages, 9 figures, submitted to Communications in Nonlinear Science
and Numerical Simulatio
A transport network for in-orbit recycling exploiting natural dynamics
This paper proposes an initial step towards the construction of a transport network connecting different orbit regimes with a Geosynchronous orbit in the Laplace plane and the Geosynchronous orbit with the Moon. This transport network will be designed to exploit a combination of natural dynamics and impulsive manoeuvres. The methodology proposed starts from the identification of regions, in orbital parameter space, around the Earth, where third-body effects concur to modify favourably the orbital elements. A sequence of manoeuvres is then devised to exploit these natural effects and achieve the desired final orbit. Conversely, the cislunar region will be connected thanks to impulsive manoeuvres and invariant manifolds, peculiar to the Circular Restricted Three-Body Problem. Finally, a perturbed two-body model is also used to identify possible disposal orbits for the decommissioned modular space assets
Satellite dynamics and space missions
This book discusses the design of new space missions and their use for a better understanding of the dynamical behaviour of solar system bodies, which is an active field of astrodynamics. Space missions gather data and observations that enable new breakthroughs in our understanding of the origin, evolution and future of our solar system and Earth’s place within it. Covering topics such as satellite and space mission dynamics, celestial mechanics, spacecraft navigation, space exploration applications, artificial satellites, space debris, minor bodies, and tidal evolution, the book presents a collection of contributions given by internationally respected scientists at the summer school “Satellite Dynamics and Space Missions: Theory and Applications of Celestial Mechanics”, held in 2017 at San Martino al Cimino, Viterbo (Italy). This school aimed to teach the latest theories, tools and methods developed for satellite dynamics and space, and as such the book is a valuable resource for graduate students and researchers in the field of celestial mechanics and aerospace engineering
Classification of regular and chaotic motions in Hamiltonian systems with deep learning
This paper demonstrates the capabilities of Convolutional Neural Networks (CNNs) at classifying types of motion starting from time series, without any prior knowledge of the underlying dynamics. The paper applies different forms of Deep Learning to problems of increasing complexity with the goal of testing the ability of different Deep Learning architectures at predicting the character of the dynamics by simply observing a time-ordered set of data. We will demonstrate that a properly trained CNN can correctly classify the types of motion on a given data set. We also demonstrate effective generalisation capabilities by using a CNN trained on one dynamic model to predict the character of the motion governed by another dynamic model. The ability to predict types of motion from observations is then verified on a model problem known as the forced pendulum and on a relevant problem in Celestial Mechanics where observational data can be used to predict the long-term evolution of the system
Dynamics of charged dust in the orbit of Venus
We study the dynamics of co-orbital dust in the inner Solar System, that is, the role of the solar radiation pressure, the Poynting-Robertson effect, the solar wind, and the interplanetary magnetic field, on the location, width, and stability of resonant motion of charged and micron-sized dust grains situated in the 1:1 mean motion resonance with Venus. We find deviations and asymmetry between L4 and L5 in the locations of the libration centers and libration width caused by nongravitational effects with analytical and numerical methods. The triangular Lagrangian points become unstable when solar radiation pressure, the Poynting-Robertson effect, and solar wind drag are considered. The Lorentz force could further destabilize the orbits, especially for small dust particles. We also compare the circular and/or elliptic restricted three-body model and a more complete model that includes all planets